The Broncos blew up in the last five minutes at Paris, conceding two tries which cost them the match and, possibly, their chance of finishing in the top four at the end of the inaugural Super League season. They can still do it, if they get back on track and other results favour them, but they cannot afford another slip-up today.
Tony Currie, the London coach, faces some enforced changes, quite apart from any he might have wanted to make after the limp finish at the Charlety Stadium.
The winger John Minto has gone home to Australia after suffering a knee injury in Paris that will need an operation. Travelling in the same direction this week was Evan Cochrane, whose shoulder injury also needs surgery.
Some consolation for Currie is the likely return of one of his Englishmen, Ikram Butt, who is available once again to play on the wing. Also returning, after a rather longer absence, is Ady Spencer, the former Cambridge University rugby league stand-off. Spencer made occasional appearances for the Broncos' predecessors, the London Crusaders, and re-emerges alongside Kevin Langer at half-back today.
If London's late collapse in Paris is a source of irritation and frustration, then the way that Leeds tossed victory away at Sheffield must be coming close to driving their coach, Dean Bell, to despair.
They had collapsed in identical fashion against Oldham a week earlier, leaving Bell to muse: "It's time we played for the full 80 minutes. To let teams come back as we have done is a crime and we must not let it happen again. You think that it might happen once, but it has happened to us three times this season and we are certainly a better team than that."
This may be true, but the league table tells an unforgiving story, with Leeds just two places and three points off the bottom and thus not entirely free from the unthinkable spectre of relegation from Super League. They will no doubt remember being beaten by London at Brentford last season, just as the Broncos were starting to emerge as a force, and Bell says that they know what to expect.
"They are a side full of Australians, many with Winfield Cup experience, so it is going to be a very tough physical game, as it always is against Australians," he says.
Leeds will throw two debutants into this potentially fraught situation - the utility back Marcus St Hilaire, whose move from Huddersfield was finalised by a transfer tribunal this week, and Adam Hughes, a young centre from the Alliance team.
"He is one of the best centres at the club at the moment, so I am giving him his chance," Bell says. "I suppose it is not the best time to give someone their debut, but knowing Adam he will not let us down."Reuse content